1. Field of the Invention
The present invention relates to an information recording apparatus and an information recording method for recording digitized content. More particularly, the present invention relates to an information recording apparatus and an information recording method, the apparatus comprising an illegal copy and reproduction preventing function for preventing stored content from being copied against an intention of a copyright owner or from being reproduced unlimitedly.
2. Description of the Related Art
As a method for applying restriction on reproduction to recorded information, in Jpn. Pat. Appln. KOKAI Publication No. 2001-195826 (Patent Document 1), there is disclosed a DVD equipment which records a pair of values in equipment incorporating flash memory and a DVD when information is recorded in the DVD and the recorded data can only be reproduced by the equipment which has carried out recording of the data.
In addition, in Jpn. Pat. Appln. KOKAI Publication No. 11-313282 (Patent Document 2), during recording, key data is generated on the basis of recording medium specific identification data and a de-scramble key, and the generated key data and scrambled data are recorded in a recording medium. During reproduction, the key data is decoded, and recovery of digital data is enabled if the recovered specific identification data and one's own specific identification data are equal to each other.
In addition, in Jpn. Pat. Appln. KOKAI Publication No. 11-630534 (Patent Document 3), when a digital broadcast is recorded, protection of a copyright is achieved by encoding and recording the equipment specific keys, keys for programs, and reproduction enable count. In Jpn. Pat. Appln. KOKAI Publication No. 11-213552 (Patent Document 4), a work key used for encoding AV data is encoded by using a disclosure key specific to an STB (set-top box), and the encoded work key is recorded together with the AV data. During reproduction, the encoded work key is recovered by using a secret key specific to STB so that reproduction can be carried out only by a system comprising the STB itself.
Further, in Jpn. Pat. Appln. KOKAI Publication No. 2003-22612 (Patent Document 5), there is disclosed a method of holding a key in recording equipment instead of a recording medium, and then, changing this key, thereby reliably eliminating the selected content on the recording medium.
Of the above patent documents, Documents 1 to 4 achieve reproduction caused by only the equipment which has carried out the recording, but fail to disclose a technique of efficiently eliminating one of the contents stored in each of the media detachable from a recording apparatus. In addition, as in a network hard disk drive having recording equipment and a plurality of recording media (HDD for example) connected to each other over a network, in the case where there is a possibility that the recording equipment and recording media are disconnected from each other or that power supplies of the recording media are turned on/off individually, there has been a problem that contents which are not required to be erased can be erased form media in an isolated state or in a power-off state.
In the above-described Jpn. Pat. Appln. KOKAI Publication No. 2003-22612 as well, in the case where a plurality of storage means exist independently of the equipment main body, if one of them is not connected or is powered off, updated information cannot be written with respect to the content recorded in that disk, and specific information contained in holding means does not coincide with information stored in the disk. As a result, there has been a problem that the content stored in that disk cannot be reproduced.